 It's not a great search. We're on to you by DigiKey and Adafruit. Every single week, Lady of User Power of Engineering to help you. Yes, you find the things that you're looking for on digikey.com. Lady, what is the great search of the week this week? Okay. So this week I'm working on this Neopixel driver board, the RP2040 Scorpio, which I was chatting about. And Neopixels are driven with this square wave that is Manchester coated. The width of the pulses is what determines the data being sent, which means you can use one wire and you don't have a clocking data in one wire. And this is going to be very handy because it's very convenient for wiring. It's very easy to do wiring. And this board has eight outputs. So you can see here, here's, oh, I'm going to the computer and I'll show the, so you have eight outputs here. And each one is driven by this high speed microcontroller, the RP2040, which is running at like 133 megahertz. And the bit pattern is 800 kilohertz clock speed. But the, and it's level shifted as well. So there's a level shifter here. You can see the 74HCT, 245BQ, which is the TDFN version, very compact version, because I didn't have a lot of space. But the thing that we've noticed is, you know, having it level shifted up to five volts is really good. You really want a nice five volt signal. But sometimes the strands of wire that reach from the neopixel driver to the neopixels can be like multiple meters. And we tell people, please don't do that. And they do it anyways. So the problem with that is, you know, you've got the capacitance of the line and you've got this very strongly driven five volt square wave. And if you combine a very strongly driven five volt square wave with a very long wire, you get ringing. And that's why normally you would have a terminator at the end, we're not gonna force people to have termination at the end. They're not gonna do it. But the good news is that, you know, the widths of the pulses can be, there can be a little bit of variability because every neopixel reshapes the waveform. And so instead what we'll do is we'll just put a little bit of resistance in line with each output. And, you know, that combined with the capacitance, it'll smooth out the curve a little bit. It'll keep it from weighing the capacitance and inductance. It'll keep it from raining as much. You'll get a little bit of a, you know, it'll be a slower rise time, but you know what, that's fine. So the only problem is that like I really had very little space left over because I needed, you know, all the feather circuitry which was here and then the RP2040, which, you know, even you can see I did a 7-7 rule. It's a two-sided board, but I had to get so many traces around. It was just difficult to make a lot of room. There's a lot of capacitors that you need and you need this flash memory and you need this crystal and you need this neopixel. So in the end, in, you know, the STEMIQT, I really had almost no space. I had like two millimeters of space. And I was, you know, I was actually trying to figure out how to fit it all in. And even a 402 resistors were like, I couldn't stack them up next to each other. And then I realized like, oh wait, I can get resistor packs in a 402. And then I realized, I don't think I've covered resistor packs on the great search. So let's go to the overhead and I'll show some off because they are very, very handy. I mean, we see them a lot in circuits, but, you know, I feel like beginners don't always know to use them. So basically, let's see, hold on, I'll make sure. Yeah, I know, I gotta back it up. There's the minimum distance. Okay. So, you know, I've got, you know, when I revised this board, for example, there are a couple of spots where I have individual resistors. The problem with individual resistors, not a problem, I love them and everything, but you do need to have pretty big pads on either side because they love to tombstone. Whereas with resistor packs, like for example, here I've got four LEDs in a row. You have four LEDs in a row and you can make them all use the same, you know, choke resistor value. One resistor pack is the same size as a single 1206 resistor or, you know, 0805 resistor, basically, but you get four in a row and another nice thing about them is they don't tombstone, I found. They, as long as you place them straight on, they are, they're wide enough and they're kind of heavy enough that they don't seem to lift as much. So, you know, the pads are smaller and it's okay and not had any issues. This is a 1K, I think it says, no, sorry, it's 472. So it's a 4.7K, because you're very bright, oh, 603 resistors. 4.7K resistor pack. The resistor packs tend to be 5%, not usually get 1% precision, although I think you can in some values. And then this one is just, it basically is just four or two resistors, you know, all in a row, but it's even more compact because you don't have to have space between them and it gets placed as one component. Likewise, on the Scorpio board here, again, I have a lot of space and, you know, I'm not against using O201s, but like, you know, O201s are tough to place. These are basically, sorry, these are O201 equivalent, these are, this is a way to four. So this is O402, sorry, these are O402 size resistors. The other ones were O603 size resistors are packed together. These are O402 packed resistors and, you know, they're very compact, but, you know, they place very nicely. I've had very few issues, even if, you know, the pitch is actually not that bad. They definitely fit within an eight mil rule and they're inexpensive. And then, you know, I was able to basically where normally the traces would go through, they fit perfectly in between all the different traces and allowed me to have a little inline resistor without a lot of effort. So let's go to the computer again. And we'll, I'll show it. So then you can see here, very compact and this spacing is almost identical to the spacing of this component, which is 0.5 mil. So these are about 0.5 mil as well, which again is very standard pitch. And, you know, you're not gonna have to spend more on manufacturing for 0.5 millimeter pitch. 0.4 is where it gets a little bit nasty or below, but 0.5 is fine. So these are well within a reason and these are four times 0.402, so these are 0.408. These are eight mil by four mil. Okay, so let's go to, oops, digickey. So let's go to resistor and I'll show you. So resistors, there's so many resistors that actually have multiple different categories. Just watch out, because it's like, you're not gonna find them in one category. There's a through hole and the surface mount, but resistor arrays are actually a totally separate category. They're not part of the surface mount resistors. I also actually use these for, I'll tell you another thing I use them for is the Spockpaw boards, which we don't really make anymore, but let me show you the kit. And these were great for the Spockpaw's, hold on, this is the, oh, it's not invisible on this image, hold on. Oh, they are, but they're stacked. Oh, here they are. So these yellow LEDs here, these are these yellow resistors over here, those are bust resistors. So they're a resistor arrays, but you get their nine pins and you get eight LEDs They all have one end connected together, they're bust and then the other end is leftover. So they're really great for LED choke resistors. Basically, each Spockpaw had like 30 LEDs. And I didn't want to also, you have to solder on the LEDs, but I really didn't want to include 30 resistors. And I wanted to have some, I wanted to have even coloring. So you have to have choke resistors. How did I minimize it? You include a resistor pack, because it was easier for people to solder. So good for surface mount and through-hole usage. But that said, we do want to have a surface mount version. We're not looking for through-hole. And then the next step, the values. So, you know, basically the value is gonna be 100 ohms. Again, you can get weird values like 1% or 0.1 once in a while, but really your resistor packs, they tend to be about like 5% only, like those are the easiest ones to get, the 5% values. So go with your nice even 2.2K, 10Ks, et cetera. They also have like voltage divider versions. I said bust versions where you have nine pins, eight resistors and they all share one common pad, but we want isolated. So they're individually separated. Each one is a unique resistor. They're just glued together side by side. They do make them in four and eight. I could have picked eight, but I happen to like the four packs and I just put down two. So I'm actually gonna do in stock and no marketplace. I just see what's in stock directly at eight. If you can see, you know, you can get the eight packs. You know, you see this a lot on like computer cards or anything that has a bus. You know, you have an eight port bus and you'll have a resistor pack or something in line or, you know, this was another eight resistor pack, 1206. We want a four resistor pack. Cause again, force two, I feel like it's too little, eight's a little bit too much. Four is less than the middle. And then I want it in that tape and reel. Secondly, I want the package. Now remember, there's basically three packages of a resistor packs. There's the 1206 package, which means it's the size of a 1206 resistor and it's equivalent to 40603 resistors back to back. There's the 0804, which is 40402 resistors back to back. And then I never use the 0502, but that's clearly the 0201 resistor. That's gonna be really tiny. I mean, you need a lot of resistors. You don't have a lot of space, go with that. I want to go with the 0804, because again, it's 0.5 mil spacing. It's within reason. And then, you know, I can just sort by, you know, price. Let's see, get a reel. Reels tend to be about 10,000 pieces. This one has a lot of stock. This looks nice and generic. Let's look at the specs. Again, 5%, you know, so just be aware, like not good for precision resistor needs. Eight pans, you know, it's kind of your standard resistor. And it's in stock. And, you know, in quantity, it's about a cent. I'll say that if you're, you know, one thing to keep in mind, because, you know, I'm trying to use more resistor packs is there's a temptation that when you look at your raw bill of material cost, it is cheaper to go with individual resistors. Like individual resistors are basically like free. They're tenth of a cent. So this is actually more expensive than for individual resistors. However, when you go into manufacturing, you're going to be paying per placement usually, because each placement takes time. And so, you know, chances are you're paying not per joint only, but per component pickup. You're paying per component pickup and your pickups are, you know, two, three cents a piece, which is pretty common. It's still gonna be cheaper to go resistor pack. So you'll be surprised. Even if I don't always use all four resistors, sometimes I'm only using two or three, it's still cheaper and faster and easier to use a resistor pack. And so you'll see, I really like them. All our STEM at QT boards have a, you know, 10K resistor pack because, and the MOSFET's dual, a dual pack, I just pick and place them. Again, they're a little more expensive than the individual, but the size and manufacturability is superior, in my opinion. So I do recommend resistor packs, even though they're not something I learned about till after I left school, because they're, you know, they're kind of like a weird mutant shape of a common part. But this is what I would, you know, I ended up picking for the inline resistors and they work lovely and they picked and placed very cleanly. So hopefully this is the last piece of the Scorpio board. I'll get that fabricated. That's a great church.